[Federal Register Volume 59, Number 46 (Wednesday, March 9, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-5419]


[[Page Unknown]]

[Federal Register: March 9, 1994]


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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 63

[AD-FRL-4846-1]

 

National Emission Standards for Hazardous Air Pollutants for 
Source Categories: Organic Hazardous Air Pollutants From the Synthetic 
Organic Chemical Manufacturing Industry and Other Processes Subject to 
the Negotiated Regulation for Equipment Leaks; Pulp and Paper 
Production; and Chromium Emissions From Hard and Decorative Chromium 
Electroplating and Chromium Anodizing Tanks: Determination of MACT 
``Floor.''

AGENCY: Environmental Protection Agency (EPA).

ACTION: Reopening of public comment period.

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SUMMARY: On December 31, 1992 (57 FR 62608), the EPA proposed standards 
to regulate the emissions of certain organic hazardous air pollutants 
from synthetic organic chemical manufacturing industry (SOCMI) 
production processes and seven other processes which are part of major 
sources under section 112 of the Clean Air Act as amended in 1990 (the 
Act). The initial public comment period closed on April 19, 1993, but 
EPA subsequently reopened the comment period for 30 days on October 15, 
1993 (58 FR 53478) to take additional comment on certain issues. In the 
final action regarding the December 31, 1992 proposal, which was signed 
on February 28, 1994, EPA deferred taking final action regarding 
provisions applicable to medium storage vessels due to the need to 
resolve an issue of statutory interpretation of section 112(d)(3)(A) of 
the Act. With this notice, EPA reopens the comment period to request 
additional comment on the appropriate interpretation of this statutory 
provision and the effect of that interpretation on the appropriate 
control requirements for medium storage vessels. The maximum achievable 
control technology (MACT) ``floor'' decision that EPA will make in this 
rulemaking will have broad precedential effect, and will presumptively 
be followed in subsequent MACT rulemakings, including the pulp and 
paper and chromium electroplating rulemakings. EPA plans to take final 
action regarding the provisions applicable to medium storage vessels 
within 90 days of publication of this notice.

DATES: Comments must be received on or before April 8, 1994.

ADDRESSES: Comments. Comments should be submitted (in duplicate if 
possible) to the EPA's Air and Radiation Docket and Information Center 
(6102), ATTN: Docket Number A-90-19, room M1500, U.S. Environmental 
Protection Agency, 401 M Street, SW, Washington, DC 20460.
    Dockets. The following dockets contain supporting information used 
in developing the proposed provisions. Docket Number A-90-19 contains 
information specific to emissions averaging and general information 
used to characterize emissions and control costs for the industry and 
Docket A-90-21 contains information on storage vessels. These dockets 
are available for public inspection and copying between 8 a.m. and 4 
p.m., Monday through Friday, at the EPA's Air and Radiation Docket and 
Information Center, Waterside Mall, Room M1500, 410 M Street, SW, 
Washington, DC 20460. A reasonable fee may be charged for copying.

FOR FURTHER INFORMATION CONTACT: On technical issues, Dr. Janet S. 
Meyer, Standards Development Branch, Emission Standards Division (MD-
13), U.S. Environmental Protection Agency, Office of Air Quality 
Planning and Standards, Research Triangle Park, North Carolina 27711, 
telephone number (919) 541-5299. For further information on the legal 
issue addressed in this notice, contact Michael S. Winer, Assistant 
General Counsel, Air and Radiation Division (2344), Office of General 
Counsel, Environmental Protection Agency, 401 M Street, SW, Washington, 
DC 20460, telephone number (202) 260-7606.

SUPPLEMENTARY INFORMATION: On December 31, 1992 (57 FR 62608), EPA 
proposed certain standards to regulate the emissions of certain organic 
hazardous air pollutants from synthetic organic chemical manufacturing 
industry (SOCMI) production processes and seven other processes that 
are part of major sources under section 112 of the Clean Air Act as 
amended in 1990 (the Act). The proposed rule is commonly referred to as 
the hazardous organic NESHAP or HON. In a separate notice, EPA is 
taking final action on virtually all aspects of that proposal but is 
deferring final action regarding the portion of the emission standards 
for emissions from one of the types of emission points covered by the 
proposal, medium storage vessels. The reason EPA is deferring final 
action regarding regulation of medium storage vessels is to reopen the 
comment period to take comments regarding the nature of the ``floor'' 
under section 112(d)(3)(A) and the appropriate level of control for 
medium storage vessels. Consequently, for purposes of this rulemaking, 
the Agency will consider only comments limited to the interpretation of 
the language in section 112(d)(3)(A) regarding the establishment of the 
``floor'' and whether the control requirements for medium storage 
vessels previously proposed by EPA would be appropriate in the event 
those proposed controls were to be determined to be more stringent than 
the floor.
    In other proposals regarding MACT standards, EPA has noted the 
possibility of two interpretations of the language in section 
112(d)(3)(A) and (B) requiring that EPA set standards no less stringent 
than ``the average emission limitation achieved by the best performing 
12 percent of the existing sources'' if there are at least 30 sources 
in a category or ``the average emission limitation achieved by the best 
performing 5 sources'' if there are fewer than 30 sources in a 
category. (See 58 FR 66078 (December 17, 1993) (pulp and paper); 58 FR 
65768, 65770 (December 16, 1993) (chromium electroplating).) In 
essence, the difference between the two interpretations is that one 
would result in the floor being established at the level of control 
that represents the average (the mean, median, or other appropriate 
statistical measure of central tendency) level of control achieved by 
the best performing 12 percent of existing sources, which would be 
generally equivalent to the 94th percentile of sources, while the other 
would result in the floor being the average level of control achieved 
by the source at the 88th percentile if all sources were ranked from 
the most controlled (100th percentile) to the least controlled (1st 
percentile).
    The first interpretation is based on grouping the words ``average 
emission limitation achieved by'' together in a single phrase and asks 
what is the ``average emission limitation achieved by'' the best 
performing 12 percent (or best performing 5 sources in the case of 
section 112(d)(3)(B)). This interpretation places the emphasis on 
``average.'' It would correspond to first identifying the best 
performing 12 percent of the existing sources, then determining the 
average emission limitation achieved by these sources as a group (i.e., 
generally the level of control achieved by the 94th percentile).
    The second interpretation groups the words ``average emission 
limitation'' into a single phrase and asks what ``average emission 
limitation'' is ``achieved by'' all members of the best performing 12 
percent. In this case, the ``average emission limitation'' might be 
interpreted as the average reduction across HAPs emitted by an emission 
point over time. Under this interpretation, EPA would look at the 
average emission limits achieved by each of the best performing 12 
percent of existing sources, and take the average limit that is 
``achieved'' by all sources within the group (i.e., the average level 
of control achieved by the 88th percentile source or the level of 
control achieved by the fifth source among the top five in the case of 
section 112(d)(3)(B)).
    The two possible interpretations are also described in detail in 
the proposals regarding the pulp and paper MACT standard (see 58 FR 
66136-137 (December 17, 1993), and the chromium electroplating MACT 
standard (see 58 FR 65768, 65770 (December 16, 1993).
    As described in section V.C.1. of the preamble to the final HON 
rule signed February 28, 1994, EPA has reevaluated and revised the 
medium storage vessel data base since the December 31, 1992 proposal. 
EPA's revised data base indicates that, for medium storage vessels, 6 
percent of the vessels are controlled with either a 90-percent 
efficient control device or an internal floating roof (IFR) or external 
floating roof (EFR) with a continuous seal. All of the controlled 
medium-sized vessels contained liquids with vapor pressures of 13.1 kPa 
(1.9 psia). The arithmetical average, or mean, characteristics of the 
top 12 percent of the medium vessels would not represent the 
performance of any known technology. However, if the median were used 
to represent the average, the floor would require control of vessels 
storing liquids with vapor pressures of 13.1 kPa (1.9 psia) or greater 
by either a 90-percent efficient control device or an IFR or EFR with a 
continuous seal. This is the same vapor pressure that was identified in 
the December 31, 1992 proposal. With the revised data base, however, if 
the floor is established at the average level of control achieved by 
the 88th percentile source, the floor would require no control. (At the 
time of the December 31, 1992 proposal, EPA had determined that about 
30 percent of medium storage vessels storing liquids with vapor 
pressures of 13.1 kPa (1.9 psia) or higher were controlled with the 
reference technology. Thus, at that time, either of the two 
interpretations of the statutory language regarding the establishment 
of the floor would have resulted in the floor being established at the 
level at which the control requirements were proposed.)
    EPA solicits comment on the proper interpretation of the statutory 
language regarding the establishment of the floor. EPA also solicits 
comment on whether the portion of the emission standard concerning 
medium storage vessels proposed in the December 31, 1992 HON proposal 
is appropriate if those proposed controls were to be determined to be 
more stringent than the floor, rather than to be at the floor as EPA 
believed at the time of that proposal. EPA intends to take final action 
regarding the provisions applicable to medium storage vessels within 90 
days of the publication of this notice.
    The MACT ``floor'' decision that EPA will make in this rulemaking 
will have broad precedential effect, and will presumptively be followed 
in subsequent MACT rulemakings, including the pulp and paper and 
chromium electroplating rulemakings. Consequently, commenters on the 
pulp and paper and chromium electroplating proposals should submit any 
comments they may have on the legal issue to the HON docket. EPA will 
consider comments on this issue already submitted in those rulemakings 
if they are resubmitted to the HON docket, but will not consider them 
in this proceeding for any purpose other than addressing the legal 
issue regarding the interpretation of the floor provisions of section 
112(d)(3).

    Dated: February 28, 1994.
Carol M. Browner,
The Administrator.
[FR Doc. 94-5419 Filed 3-8-94; 8:45 am]
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